Output Transformer

Output Transformers allow you to modify every form field value differently for each given channel before submitting them to a given output workflow channel.

Available Core Transformer

If no transformer has been found, the fallback_transformer will be used.

Available Transformer	Field	Channel	Service
date_transformer	date, datetime, time, birthday	object	@OpenDxp\Bundle\FormBuilderBundle\Transformer\Output\DateDataObjectTransformer
choice_transformer	choice, dynamic_choice	object	@OpenDxp\Bundle\FormBuilderBundle\Transformer\Output\ChoiceDataObjectTransformer
country_transformer	country	object	@OpenDxp\Bundle\FormBuilderBundle\Transformer\Output\CountryDataObjectTransformer
fallback_transformer	All others	_all	@OpenDxp\Bundle\FormBuilderBundle\Transformer\Output\FallbackTransformer

Override default Output Transformer

If you want to transform the text field value for example, you need to add your own transformer. First, let FormBuilder know about your transformer.

You're also able to set up your custom input transform for your dynamic fields via the input_transformer configuration node.

form_builder:
   types:
       text:
           output_transformer: text_input_transformer

Now you need to register your new and shiny transformer. Since there is no default text field transformer, you could apply this transformer to all channels.

    App\OutputTransformer\TextInputTransformer:
        autowire: true
        tags:
            - { name: form_builder.transformer.output, type: text_input_transformer, channel: _all }

If you want to apply this transformer to the object output channel only, change the channel:

    App\OutputTransformer\TextInputTransformer:
        autowire: true
        tags:
            - { name: form_builder.transformer.output, type: text_input_transformer, channel: object }

---

After that, you have to set up a PHP-Service:

<?php

namespace App\OutputTransformer;

use Symfony\Component\Form\FormInterface;
use OpenDxp\Bundle\FormBuilderBundle\Model\FieldDefinitionInterface;
use OpenDxp\Bundle\FormBuilderBundle\Transformer\Output\OutputTransformerInterface;

class TextInputTransformer implements OutputTransformerInterface
{
    public function getValue(FieldDefinitionInterface $field, FormInterface $formField, $rawValue, $locale)
    {
        // manipulate or change the value
        return $rawValue;
    }

    public function getLabel(FieldDefinitionInterface $field, FormInterface $formField, $rawValue, $locale)
    {
        // manipulate or change the label
        return $rawValue;
    }
}

---

Custom output transformer

After you've created a custom output channel, you may want to control the output values too. It is possible to use one transformer for all available fields, like we'll show you below. If you want to add a fallback to all the other fields in your channel, you need to add a tag with type fallback_transformer.

Note: If you don't add any transformer, the fallback_transformer will be used again.

App\OutputTransformer\MyChannelOutputTransformer:
    autowire: true
    tags:
        - { name: form_builder.transformer.output, type: date_transformer, channel: myChannel }
        - { name: form_builder.transformer.output, type: choice_transformer, channel: myChannel }
        - { name: form_builder.transformer.output, type: choice_transformer, channel: myChannel }
            # To use this transformer also for all the other fields, use the fallback_transformer.
            # In fact, if you're removing the tags above, this fallback will be used on every field
        - { name: form_builder.transformer.output, type: fallback_transformer, channel: myChannel }

Target Aware Transformer

In some rare cases you may need the target field, before you're able to map the data. In our object output channel for example, it's allowed to map choice values to dropdowns but also to input fields.

<?php

namespace App\OutputTransformer;

use Symfony\Component\Form\FormInterface;
use OpenDxp\Bundle\FormBuilderBundle\Transformer\Target\TargetAwareData;
use OpenDxp\Bundle\FormBuilderBundle\Transformer\Target\TargetAwareValue;
use OpenDxp\Bundle\FormBuilderBundle\Model\FieldDefinitionInterface;
use OpenDxp\Bundle\FormBuilderBundle\Transformer\Output\OutputTransformerInterface;
use OpenDxp\Model\DataObject\ClassDefinition\Data\Input;
use OpenDxp\Model\DataObject\ClassDefinition\Data\Multiselect;
use OpenDxp\Model\DataObject\ClassDefinition\Data\Select;

class MyTargetAwareOutputTransformer implements OutputTransformerInterface
{
    /**
     * {@inheritdoc}
     */
    public function getValue(FieldDefinitionInterface $fieldDefinition, FormInterface $formField, $rawValue, $locale)
    {
        return new TargetAwareValue([$this, 'getTargetAwareValue']);
    }

    /**
     * @param TargetAwareData $targetAwareData
     *
     * @return mixed|null
     */
    public function getTargetAwareValue(TargetAwareData $targetAwareData)
    {
        $rawValue = $targetAwareData->getRawValue();
        $target = $targetAwareData->getTarget();

        if ($target instanceof Select) {
            return is_array($rawValue) ? $rawValue[0] : $rawValue;
        } elseif ($target instanceof Multiselect) {
            return !is_array($rawValue) ? [$rawValue] : $rawValue;
        } elseif ($target instanceof Input) {
            return is_array($rawValue) ? join(', ', $rawValue) : $rawValue;
        }

        return $rawValue;
    }

    /**
     * {@inheritdoc}
     */
    public function getLabel(FieldDefinitionInterface $field, FormInterface $formField, $rawValue, $locale)
    {
        return null;
    }
}